Treatment of vascular occlusions using elevated temperatures

Abstract

A method for providing a therapeutic effect to a treatment site within a patient's vasculature comprises positioning a catheter at the treatment site. The catheter includes a heating element and a fluid delivery lumen that is coupled to an exit port within a distal region of the catheter. The method further comprises passing the therapeutic compound through the delivery lumen and the exit port at a flow rate. The heated therapeutic compound is provided to the treatment site. The method further comprises exposing at least a portion of the treatment site and at least a portion of the delivered heated therapeutic compound to ultrasonic energy generated by the ultrasound radiating member.

1 . A method comprising: 
 positioning an elongate catheter within a blood vessel having a blood carrying capacity, wherein the catheter includes a fluid delivery lumen having an exit port within a distal region of the catheter;    passing a therapeutic compound through the fluid delivery lumen, through the exit port, and into the blood vessel;    increasing the temperature of a region adjacent to the distal region of the catheter; and    increasing the blood carrying capacity of the blood vessel.    
   
   
       2 . The method of  claim 1 , wherein increasing the temperature comprises delivering ultrasonic energy to the region adjacent to the distal region of the catheter.  
   
   
       3 . The method of  claim 1 , wherein the therapeutic compound is passed into the blood vessel before the temperature of the region adjacent to the distal region of the catheter is increased.  
   
   
       4 . The method of  claim 1 , wherein the therapeutic compound is passed into the blood vessel after the temperature of the region adjacent to the distal region of the catheter is increased.  
   
   
       5 . The method of  claim 1 , wherein the therapeutic compound is passed into the blood vessel while the temperature of the region adjacent to the distal region of the catheter is increased.  
   
   
       6 . The method of  claim 1 , wherein the therapeutic compound is selected from the group consisting of heparin, urokinase, streptokinase, tPA and rtPA.  
   
   
       7 . The method of  claim 1 , wherein the temperature of the region adjacent to the distal region of the catheter is increased to a temperature that is less than or equal to about 43° C.  
   
   
       8 . The method of  claim 1 , wherein the temperature of the region adjacent to the distal region of the catheter is increased to a temperature that is between about 38° C. and about 43° C.  
   
   
       9 . The method of  claim 1 , wherein increasing the temperature is accomplished by heating the therapeutic compound before passing the therapeutic compound through the fluid delivery lumen, through the exit port and into the blood vessel.  
   
   
       10 . A method of treating a vascular obstruction at a treatment site within a patient's vascular system, the method comprising: 
 positioning an elongate catheter within the patient's vascular system;    exposing the vascular obstruction to a therapeutic compound delivered from the elongate catheter; and    exposing the vascular obstruction and the therapeutic compound to ultrasonic energy in a quantity sufficient to increase a blood carrying capacity of the treatment site, wherein the ultrasonic energy is delivered from the elongate catheter.    
   
   
       11 . The method of  claim 10 , wherein exposing the vascular obstruction and the therapeutic compound to ultrasonic energy causes the treatment site to remain at a temperature between about 38° C. and about 43° C. for at least about 5 minutes.  
   
   
       12 . The method of  claim 10 , wherein exposing the vascular obstruction and the therapeutic compound to ultrasonic energy causes the treatment site to remain at a temperature between about 38° C. and about 43° C. for at least about 15 minutes.  
   
   
       13 . The method of  claim 10 , wherein the elongate catheter is positioned such that a distal portion of the elongate catheter is within the vascular obstruction.  
   
   
       14 . The method of  claim 10 , further comprising monitoring the temperature of the treatment site while exposing the vascular obstruction and the therapeutic compound to ultrasonic energy.  
   
   
       15 . The method of  claim 10 , further comprising: 
 monitoring a temperature of the treatment site while exposing the vascular obstruction and the therapeutic compound to ultrasonic energy; and    displaying the monitored temperature on a user interface.    
   
   
       16 . The method of  claim 10 , further comprising delivering a cooling fluid to the treatment site while exposing the vascular obstruction and the therapeutic compound to ultrasonic energy.  
   
   
       17 . The method of  claim 10 , wherein: 
 the ultrasonic energy is delivered from an ultrasonic transducer positioned within the elongate catheter;    a voltage different is applied across the ultrasonic transducer.    
   
   
       18 . An apparatus comprising: 
 a tubular body having a fluid delivery lumen that is hydraulically coupled to an exit port in a distal region of the tubular body, wherein the tubular body is configured to be positioned within a blood vessel;    a heating element positioned within the distal region of the tubular body; and    a control system configured to maintain a selected portion of the blood vessel that is adjacent to the distal region of the tubular body within a temperature range for a specified period of time, wherein maintaining the temperature range for the specified period of time is sufficient to increase a blood carrying capacity of the selected portion of the blood vessel.    
   
   
       19 . The apparatus of  claim 18 , wherein the control system is further configured to deliver a therapeutic compound through the fluid delivery lumen and the exit port.  
   
   
       20 . The apparatus of  claim 18 , further comprising a guidewire configured to be received in a utility lumen defined by the tubular body.  
   
   
       21 . The apparatus of  claim 18 , wherein the fluid delivery lumen is hydraulically coupled to a plurality of exit ports in the distal region of the tubular body.  
   
   
       22 . The apparatus of  claim 18 , wherein the exit port is located along a longitudinal axis of the tubular body.  
   
   
       23 . The apparatus of  claim 18 , wherein the heating element is selected from the group consisting of an ultrasound transducer, a radiofrequency element and a thermoelectric device.  
   
   
       24 . The apparatus of  claim 18 , further comprising a temperature sensor coupled to the tubular body, wherein the temperature sensor is configured to measure a temperature of the selected portion of the blood vessel.